Algodoo

Nice demonstration! My only suggestion is to reduce the precision of the force gage readouts (to maybe 2 or 3 decimal places) and reduce their jitter. I think you already know how to do that, but if not, I'll show you.

This would be a great scene for a first-year physics class.

Thanks for the suggestion. This scene is deceptively simple, but I thought it was interesting because it operates as a feedback control circuit where the motor/pulley combination act like a force amplifier that is governed by negative feedback from the slack side of the rope. I did this experiment a while ago in real life with nylon monofilament and aluminum pulleys and was amazed at the how constant the force was. My recollection was that the force uniformity was limited mainly by the eccentricity of the pulleys which were out only a few thousandths of an inch. You can increase the speed of the pulleys and the force will not change.

Nice job. I gave it a 10.

Nice. It would be neat if it could work no matter where the spring is. Maybe you could script each end of the spring to know its position relative to the other, so it could measure force based on how far apart each end of the spring is.

Believe it or not AIR FRICTION has a major effect on how this device operates! When I turn off the air friction, I can no longer get a stable reading, because the mechanism wants to oscillate. When I make the air friction much stronger, then it takes much longer to get a reading because the mechanism responds much more slowly.

STRANGE!

That is because I set autoBend = false and airFrictionMult = 100.0 for the rope, in an attempt to reduce force variation along the slide.

Oh okay, now it makes sense why that's happening.